The use of polymers has grown substantially with time. Polymers are now being used in many areas previously occupied by metals, glass and/or other materials. As a result, polymers are now exposed to a variety of elements that normally cause polymers to degrade, such as ultraviolet (“UV”) light. As such, it has been a goal to provide polymers having improved weatherability such that these polymers are better able to maintain their visual and/or structural usefulness for greater periods of time.
In one prior art solution, the use of polyesters containing resorcinol arylate chain members has been utilized to provide good resistance to the yellowing and/or loss of gloss that occurs when polyesters are exposed to UV light, and thus are considered to possess good “weatherability.” The arylate moieties in these polymers typically contain isophthalate, terephthalate, and mixtures of isophthalate and terephthalate. Polyesters of resorcinol arylates can provide effective protection against yellowing and loss of gloss when coated over a resinous substrate.
Another solution has been in the creation of thermosetting fluororesin coating materials that offer effective weather resistance. These thermosetting fluororesin coating materials are used in many outdoor structures, such as gates, fences, building materials and automobiles. These materials have been applied in a coating form and are capable of being used to achieve a gloss finish or a matte finish.
However, when used in a powder coating, these fluororesins typically display lower surface hardness. Furthermore, these fluororesins are significantly more costly than conventional powder coatings. Finally, as the name suggests, these resins contain fluorine, which may cause disposal issues (either of the coating or the entire coated article at the end of its lifetime). Therefore, customer acceptance is limited for these coatings and they only hold a small market share despite their outstanding weatherability.
Accordingly, it would be beneficial to provide a polymer coating material that is capable of being used in a powder coating system. It would also be beneficial to provide a polymer coating that exhibits improved weatherability characteristics while also being capable of providing a selected coating finish.